Optical technique for color imaging of temperature gradients in physiological media: a method to study thermal effects of cw and pulsed lasers

Rudolf M. Verdaasdonk*, Cornelius M.D. Borst

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

11 Citations (Scopus)
1 Downloads (Pure)

Abstract

Application of the thermocamera is limited to imaging surface temperatures at an air interface. We describe a technique which enables color imaging of temperature gradients inside optically transparent media. In an optical setup, very small changes in optical density of the media, induced by flow or temperature gradients, are color coded. Depending on the geometry of the temperature distribution, colors in the image can be related to absolute temperatures. The calibration is performed by making use of calculated temperature distributions of specific geometry and by thermocouple measurements. This technique can be applied to study the thermal effects of cw and pulsed lasers during interaction with model and biological tissues. Using fast flash light photography or video imaging, temporal resolution in the microsecond region can be obtained. To study the feasibility of the technique, experiments were performed to image cw Nd:YAG and pulsed Holmium and Excimer laser light interaction with transparent gels and tissues submerged in saline. During the measurements, temperatures were also monitored using thermocouples on selected positions within the field of view. At present, it is still difficult to translate the color images directly to absolute temperature images. The real time color images obtained with this color schlieren technique, however, provide a good understanding of thermo dynamics and thermal relaxation during laser tissue interaction with cw and pulsed lasers.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSPIE
Pages355-365
Number of pages11
ISBN (Print)0819411094
DOIs
Publication statusPublished - 1 Jan 1993
Externally publishedYes
Event4th Laser-Tissue Interaction Conference 1993 - Los Angeles, United States
Duration: 18 Jan 199320 Jan 1993
Conference number: 4

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1882
ISSN (Print)0277-786X

Conference

Conference4th Laser-Tissue Interaction Conference 1993
CountryUnited States
CityLos Angeles
Period18/01/9320/01/93

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